Bacterial Kidney Disease (BKD) - FHP

Science Center Objects

Fish Diseases

Bacterial Kidney Disease (BKD)

Photo of scientist at loading gel

Nested polymerase chain reaction (nPCR) for the detection of Renibacterium salmoninarum. Agarose gel electrophoresis is used for size separation and visualization of amplified DNA sequences. Credit: USGS - Western Fisheries Research Center. (Public domain.)

Renibacterium salmoninarum is the causative agent of bacterial kidney disease (BKD), a serious disease problem of wild and cultured salmonid fishes worldwide. Control of the bacteria by use of antibiotics is difficult due to its slow growth, and conventional vaccine strategies are ineffective or may actually worsen the disease state. Furthermore, the bacteria can be passed not only between fish in the same water system (horizontal transmission), but also from one generation to the next via infected eggs (vertical transmission). During infection, R. salmoninarum can evade immune surveillance by surviving and replicating within host macrophages (a type of white blood cell). Also, R. salmoninarum produces large amounts of a unique protein (p57) which suppresses a number of immune functions. Control of R. salmoninarum will require a better understanding of the bacteria itself, the salmonid immune system and how the bacteria and host defenses interact.